Dobby drive



Aug. l5. 1933. J. G. BENTLEY E1- AL BOBBY DRIVE Filed Feb. 18, 1931 2 Sheets-Sheet 1 INVENTOR5 A TTORNE Y.

Aug. 15, 1933. J. s. BENTLEY E-r AL DOBBY DRIVE Filed Feb. 18, 1951 2 Sheets-Sheet 2 *I T/D-A- Cz) b @15,777

NVENTORS' A TTORNE Y.

Patented Aug. 15, 1933 UNITED STATES DOBBY DRIVE John G. Bentley and Robert A. Gibbs, Jr., Greensboro, N. C

Application February 18, 1931. Serial No. 516,585

9 Claims.

This invention relates to means for actuating the dobby mechanism of a dobby loom, and more especially to means for imparting proper movement to the jack-knives in the dobby head of a dobby loom.

It is a well-known fact that the jackknives engage certain jacks in a dobby head, and associated with each jack is a portion of the harness mechanism and it is also well understood that when the pattern chain allows a certain jack to Aengage the jackknife that the movement of the jackknife causes the jack to be moved and, therefore, the harness associated with said jack is raised upwardly, and when the jackknife recedes, the said harness lowers itself by gravity or tension means.

When certain of the harness are in raised position and other of the harness are in lowered position, it forms a space between the warp threads ing operation, and it is an object of this invention to provide means whereby the movement of the jack and the associated harness and also the jack knives are not moved at a uniform rate of speed,

but wherein the travel is slow at first, then gradually increases in swiftness, and then gradually decreases in speed at the end of the raising and lowering operations imparted to the harness, so that the raising and lowering operations are regulated so as to impart to the warp threads a slow movement whenY the movement begins and then imparting the Vgreatest speed at the time the threads cross a common plane, so as to cause the space thru which the shuttle is thrown to be closed the minimum amount of time.

The scotch yoke used for transmitting the circular motion to the dobby drive arm from the elliptical gear is used to eliminate unequal throw and a variation in speed inV a crank arrangement. The cross head member when dri en toward and awayfrom the common center of a crank, pauses longer when at the end of its stroke toward the common center than it does at the end of its stroke away from the common center.

The purpose of the yoke-at the top is to permit a horizontal movement of a fixed point on the dobby rocker. arm in relation to the vertical motion transmitted to a iixed point on the arm by a vertical action of the yoke and thereby equalizing the stroke of each dobby knife. These arrangements transmit the same amount of stroke to both the top and bottom dobby knives at the same speed of travel in a given length of time.

Heretofore, one type of actuating means for the rocker arm and jackknives for dobby looms has been in the form of a crank driven by the loom and having a connecting rod connecting the crank and the rocker arm. It is a well known fact that where a connecting rod is connected to a rotary crank with ksaid connecting rod having through which the shuttle is thrown in the weavrocker arm, that the speed of the rocker arm at the tcp of its stroke is greater than at the bottom of its stroke, due to the fact that at the center of rotation of crank and connecting rods are both above the outer extremity of the crank and their arcs of swing, tend to coincide, while when at the top of the stroke of the crank the arcs of crank and connecting rod are opposed to each other as their centers of rotation are on opposite sides of their point of connection. It is an object of this invention to eliminate this defect in the present structure by the use of the scotch yoke for connecting the connecting rod to the driving member,

and therefore, eliminating any swinging movement being impartedY to the connecting rod.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds when taken in connection with the accompanying drawings, in which- Figure 1 is a sidel elevation of the dobby actuating mechanism shown associated with one end of a loom;

Figure 2 is an end elevation looking from the right hand side of Figure 1;

Figure 3 is a View similar to Figure 1, but showing the structure on an enlarged scale;

Figure 4 is a view similar to Figure 2 Vbut showing the structure'on an enlarged scaleand showing the upper portion thereof in cross-section, which cross-sectional part is taken along the line 4-4 in Figure 3;

Figure 5 is a View of the upper central portion of Figure 4 with the front portion and shaft 38 removed, andv being taken along line 5-,5 in Figure 6; Y V

Figure 6 is a cross-sectional view taken along the line 6-6 in Figure 3;

Figure 7 is a side elevation of the adjusting nut in the central portion of the device. V

Figure 8 is a side elevation ofY gear 83 showing the slots.

Figure 9 is a longitudinal sectional View through the means for securing connecting rod to the elliptical gear and also for securing the connecting rod to the rocker arm.

Referring more specically to the drawings the numerallo indicates the framework of a loom to which is secured a bracket 11 by means of bolts 12 and 13 and this bracket has a lower` extension thereonl indicatedY by the reference character 14 and an upwardly extending arm 15 which arm has integral therewith an extension 16 which is secured to the framework of the loom by means of a screw 17 and this portion 15 has a bearing portion 18 whichis integral with portions 15 andV 16 and the upper end of this portion 18 has a cup 19 for the reception of a lubricant which `has a hole 20 communicating with the interior thereof. This oil hole 20 has a wick 21 therein which communicates with the interior of the bearing formed by said member 18 and associated parts. This member 18 has four laterally projecting lugs 22, 23, 24 and 25 which coincide with lugs 26, 27, 28 and 29. Bolts 30, 31, 32 and 33 penetrate these lugs for securing the parts 18 and 34 together, the other half of the bearing corresponding to 18 being indicated by reference character 34. ,Y Y

The members 18 and 34, when placed together, form a vertical passageway which is square in cross-section and in the tcp and bottom portions thereof bearing members are fitted, said bearing members being indicated by reference characters 35 and 36, and similar reference characters apply to the bearings in the lower portion of this member formed by parts 18 and 34.

A squared shaft 38 is adapted to have sliding movement in these bearings composed of parts 35 and 36, and to the upper end of the squared shaft 38 is secured a scotch'yoke 40 by means of screws 41 and 42 which scotch yoke has an elongated slot 43 therein in'which roller bearing 44 is adapted to have movement, said roller bearing 44 being mounted on tubular member 45 which has a collar 46 integral therewith. Bolt 47 penetrates member 45 and is threadably secured in nut 48 which fits in hole 48a in the rocker arm 52, and a washer 48h loosely fits around bolt 47, which bolt has a head 79 thereon to press washer 48D against end of member 45 to form a bearing surface between washer 48D and collar 46. An oil cup 49 is threadably secured in an interior bore 50 of this bolt 45 which communicates with the interior of roller Ybearing 44. This bolt has secured thereon gear 83er rocker arm 52 of the jackknife actuating member which rocker arm has arms 53 and 54to whichare loosely secured rods 55 and 56, the other ends of said rods having jackknives 57 and 58 for actuationof the jacks and harness mechanism of the dobby. This member composed of parts `52, 53, and 54 `which are integral with each other is pivotally mounted on member 59.

The lower end of squared shaft38 has a left hand thread 64 thereon on Which -isrthreadably mounted in bushing 65 which, in turn, has right hand threads thereon and is threadably secured in the upper end of a member 66, said member 66 having lugs 67 and 68 projecting therefrom with a screw 69 therein by means of which the bushing 65 can be adjusted, and bushing 65 has iis mounted a structure identical to that shown in Figure 9, and the parts of which bear the same reference characters. The bearing beingidentical to that shown for connection to thev rocker arm, being identical a further description is not deemed necessary. Bolt 45 is adjusted longitudinally of a slot in rocker arm 52 for proper vadjustment. Also bolt 47 is adjusted along slot 83o to give the desired length of travel to the member 38 and the jackknives. In the drawings, the adjustment is near the inner part of slot 83h to give a short throw to the jackknives, but as bolt 47 is adjusted further outward inslot 83h a greater length of .travel will be imparted to the jack- .knives. Another slot 83hV is shown, as both `these slots are providedLto permit the mechanism to be used with right hand or left hand looms. This gear wheel 83 is fixedly secured on stud shaft 84 which is rotatably mounted in bearing 85, and a collar 86 is secured on the outer end thereof by any suitable means such as set screw 87, to permit rotative movement of shaft 84.

To the lower side of member 74 there is secured another squared shaft 88 by means of screw bolts 89 and 90. This squared shaft 88 projects downwardly into a bearing formed of portions 91 and 92, which are cast integral with each other on one side of the bearing receiving portion and are separated from each other on the other side and can be adjustably secured to each other'to hold bearing members in place, by means of screws 93 and 94, the bearing in said portion being identical to the split bearing indicated by reference characters 35 and 36 in Figures 5 and 6.

The portions 91 and 92 are integral with bracket 11 and associated therewith is a lubricant receptacle 95 which has a wick 96 therein which passes thru hole 97 in the sidewall of bearing portion 91 and also passes thru the splitY bearing contained therein for furnishing lubricants to the squared shaft 88.

The conventional crank shaft of the loom is indicated by the reference character 100 and this has a spur gear 101 eccentrically mounted thereon, which gear meshes with the elliptical gear 83. The ratio of the gears 161 and 83 is such that gear 101 makes two'revolutions while gear 83 makes one'revolution, so that for one complete revolution of the crank shaft the jack knives will be operated in one direticn, and for the succeeding revolution of gear 181 the jack knives will be moved in the other direction.

The operation of the mechanism is as follows: By referring to Figures 1 and 2 of the drawings, it will be seen that the portion b of gear- 101 has a'small radius, whereas, portion a of gear 101 has a large radius, and portions c and the desired result. In operation, the crank shaft 100 will be turning in a clock-wise direction as viewed in Figure 2, and when the portion b is in engagement with the portion e or f of gear 83, a slow movement will Ybe imparted to thegear and the jackknives, whereas, when the porf tion a of gear 101 is moving along the portion c or dof gear 83, a rapid movement will be imparted to gear 83 and the jackknives for the c or d as the case may be which has a small radius, the gear 83 also will be moved faster reason that the portion a has a large radius and will be moving relatively faster or will move j the gear 83 faster and also on account ofthe portion a being in engagement with the portion so that it is seen that theY maximum of speed is obtained while the portion a of gear 101 is Vmoving along portion'c or d of gear 83, and

when the bolt 45 reaches a position, either in the downward movement or upward movement,

which is approximately in horizontal alinement A shuttle to be thrown therethrough, and at each pick of the loom or at each several picks of the loom, depending upon the pattern desired to be woven, the pattern control chain causes a shifting of the warp threads by allowing certain of the harness to be lowered and certain of the harness to be raised, andthe invention as above described causes a relatively slow movement to be imparted to the harness mechanism at the` beginning of the lowering or raising operation and, therefore, causes the space through which the shuttle is thrown to be held in open position the maximum length of time, and when the change does occur by lowering certain warp threads, and raising certain other warp threads for the throwing of the next shuttle, this crossing of the threads vertically is performed in a minimum amount of time on account of the variable speed at which the jackknife is driven and thus prevents floats, pickouts, and other imperfections in the weaving of the cloth.

Heretofore in other drives for dobby rocker arms where the stud in the end of the rocker arm 52 could not have any movement with relation to the driving rod,.it was necessary in order to give the same speed to both of the jackknives in a given length of time, to find a point of starting, to pull the rocker arm 52 below dead center and adjusting the portions 53 and 54 of the rocker arm at a proper angle with relation to the vertical so Vas to impart to the jackknives an equal stroke in a given amount of time and by providing the slot 43. This adjustment is not necessary because the pin 45 automatically seeks the proper point in the slot so as to impart an equal lengthY of stroke at a uniform speed to the jackknives and as shown in the drawings, the bolt 47 is adjustably mounted in slot 83-B so as to adjust the length of the stroke imparted to member 38 and when proper adjustment is effected, the portion of the rocker arm indicated by 53 and 54 will have its longitudinal center parallel to shaft 38, when all the warp threads are in the same plane, as when the rocker arm is in neutral position with stud shaft 47 in the same horizontal plane as shaft 84.

YIn the drawings and specification there is set forth a preferred embodiment of the invention and although specific terms are employed they are used in a generic and descriptive sense only, and not for purposes of limitation, the scope of the invention being set forth in the appended claims.

We claim:

1. In a dobby loom having a dobby head and a rocker arm, means for rocking said rocker arm comprising an elliptical gear and an eccentric gear meshing therewith, said elliptical gear having a slot therein, a connecting rod having its upper end connected to the rocker arm and having a transversely disposed slot in its lower portion, means mounted'in both of said slots for connecting the elliptical gear with the connecting rod, and means for driving said elliptical gear in timed relation to said loom. v

V2a. Means for operating the jackknives in a dobby loom comprising a dobby rocker arm having a lever portion, a framework adapted to be secured to the loom, a vertically reciprocating member mounted in said framework and having a horizontally disposed slot in the upper end thereof in which the lever portion of the dobby rocker arm is slidably mounted, an elliptical gear rotatably mounted in the framework, said vertically reciprocating member having a second horizontally disposed slot therein, said elliptical gear having a slot therein, a stud is adjustably mounted in said slot in said elliptical gear, means for loosely securing one end of said stud in said second slot in the vertically reciprocating member, and an eccentrically mounted gear on one of the driven shafts of the loom, 'said last gear meshing with said elliptical gear to impart vertical variable movement to the reciprocating member and the rocker arm associated therewith.

3. Means for actuating the rocker arm in a dobby loom comprising a bracket having means for attaching the same to the framework of the loom, a member slidably mounted in said bracket, an elliptical gear rotatably mounted in the bracket, said gear having a slot therein, a stud adjustably mounted in said slot, means for loosely securing the stud to said reciprocating member, an eccentric gear driven by the loom and meshing with the elliptical gear for imparting movement to the rocker arm.

4. Harness actuating means for dobby looms having a rocker arm, comprising a slidable member having two transversely disposed slots therein spaced apart from each other, means for securing the rocker arm in one slot, an eccentric gear driven by the loom, an elliptical gear driven by the first gear, and means on said elliptical gear having engagement with the other slot in said slidable member for driving the same.

5. In a drive for the rocker arm of a dobby head for looms, a vertically reciprocating shaft and bearings therefor, said shaft having a transversely disposed slot intermediate the ends thereof and another transversely disposed slot therein at the upper end thereof, means for slidably mounting the free end of the rocker arm in the last-named slot, and means for securing a driving means in the rst-named slot for imparting reciprocatory motion to said shaft.

6. Means for driving the rocker arm of a dobby head for looms comprising a slidable shaft, bearings for the shaft, a scotch yoke in said shaft intermediate the ends thereof and also having a scotch yoke at the upper end thereof, means for loosely securing the free end of the rocker arm in the upper yoke and means for loosely securing driving means in the yoke intermediate the ends of the shaft, said driving means having means for moving the same in a circular path, and means for imparting a variable speed to said driving means.

7. Driving means for the rocker arm of a dobby loom comprising a shaft having a scotch yoke at the upper end thereof and also another scotch yoke at another point on said shaft, means for connecting the rocker arm to the yoke in the end of the shaft and driving means connected to the other yoke.

8. Driving means for the rocker arm ofV a dobby loom comprising a shaft having two scotch yokes therein, means for securing the rocker arm in one yoke, means for reciprocating the shaft, and means for connecting said reciprocating means to the-other yoke.

9. Means for driving a rocker arm in a dobby head for looms comprising a reciprocable member having two transversely disposed slots therein,

means for connecting the rocker arm in one slot, 

